[Libguestfs] Virt-v2v conversion issue

VONDRA Alain AVONDRA at unicef.fr
Tue Oct 14 07:56:22 UTC 2014

The version libguestfs-winsupport installed is well 7.1-3.el7 and the qemu-kvm-rhev is 2.1.2-2.el7
In fact the qemu-img convert hangs.

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-----Message d'origine-----
De : Richard W.M. Jones [mailto:rjones at redhat.com]
Envoyé : mardi 14 octobre 2014 08:44
À : VONDRA Alain
Cc : libguestfs at redhat.com
Objet : Re: [Libguestfs] Virt-v2v conversion issue

The ioctl failure is not an error, but it's unexpected, and maybe hints at something deeper.

What version of libguestfs-winsupport is installed?  It should be
7.1-3.el7 (assuming this is RHEL 7), which has support for fstrim of aligned NTFS partitions.

- - -

Now on to the real problem ... 'qemu-img convert' is running, and then fails.  Does it hang or crash?  I would enable core dumps and capture one, since there's obviously a bug in qemu-img:

(1) As root do:

  echo core.%p > /proc/sys/kernel/core_pattern

(2) Before running virt-v2v, do:

  ulimited -c unlimited

and you should get a core.* file in the current directory when qemu-img segfaults.  Attach that file to gdb to get a stack trace:

  gdb /usr/bin/qemu-img core.XYZ
  (gdb) t a a bt

It's very unexpected for qemu-img convert to fail, especially from a raw format local disk.  But bugs can happen ...

If qemu-img is hanging, not crashing, then you can attach gdb directly to the process and get a stack trace that way.

What version of qemu-kvm-rhev is this?

- - -

If fstrim is successful then it should greatly reduce the amount of data to copy, both saving you lots of time and making the 'qemu-img convert' bug harder to hit.


Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-df lists disk usage of guests without needing to install any software inside the virtual machine.  Supports Linux and Windows.

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